3D Printing on OpenBSD

and how to port python apps to OpenBSD!

Overview of 3D Printing

• Modeling (or finding) what you are going to print.
• Slicing.
• Printing.

Modeling

This is an entire talk in and of itself, however, you have lots of choices!

** Output Printer Friendly Files*

Finding things to print

Many objects have already been created, so search first, create later!

• Thingiverse
• Repables
• Magicube

Slicing

What the heck is slicing? Why do we need it?

Have you ever done the “Robot Programming” exercise?

Slicing (cont…)

Slicing is basically cutting a 3D model into commands that the printer turns into physical actions (think Robot Programming.. go forward 3 steps, turn left).

Generally slicers produce G-Code which is the final format printing apps like OctoPrint use.

Reasons for slicing

• Controllers on 3D printers are fairly basic, can’t run large code base.
• 3D objects need to be represented in a linear set of instructions.
• 

Roberto approves!

Robot Programming

Robot Code

forward(3);
turn('Left');

G-Code

G01 X114.395 Y115.288 F1080.000

Not really a one to one - but you get the idea :D

Slicing Applications

Printing

Once the model is converted to G-Code, we are ready to print with some kind of printing app!

Printing Application

There are many more apps that can be used!

Making an apple pie from scratch

Porting 3D printing apps to OpenBSD using the magic that is the ports system!

Gathering requirements

Usually this is a go-until-failure kinda thing, but sometimes you get a break!

OctoPrint has a list of required python modules included in the github repo!

Searching the ports tree with make search key=<item> reveal we are missing 4 of the required libs.

Find source

Fortunately for us the reqs are all on PyPI and ports has facilities for grabbing stuff from there!

Make a Makefile

Now we build our Makefile! You can use /usr/ports/infrastructure/templates/Makefile.template, or copy an existing PyPI port.

Here is a Makefile for py-flask-login (white space removed for slide)

COMMENT =		user session management for flask
MODPY_EGG_VERSION =	0.2.11
DISTNAME =	  	Flask-Login-${MODPY_EGG_VERSION}
PKGNAME =		py-${DISTNAME:L}
CATEGORIES =		www
HOMEPAGE = 		https://github.com/maxcountryman/flask-login
# MIT
PERMIT_PACKAGE_CDROM =	Yes
MASTER_SITES =	     	${MASTER_SITE_PYPI:=F/Flask-Login/}
MODULES =    		lang/python
RUN_DEPENDS +=		www/py-flask
MODPY_SETUPTOOLS =	Yes
.include <bsd.port.mk>

Important bits

MASTER_SITES =	     	${MASTER_SITE_PYPI:=F/Flask-Login/}

This bit of magic tells the ports system to grab a tarball from PyPI

For a more comprehensive list of available MASTER_SITES check out:

/usr/ports/infrastructure/templates/network.conf.template

Testing the MASTER_SITE

Once we have our Makefile in place we can test the fetching of our DISTFILE with make fetch.

If all goes well you will see a progress bar showing the file you expected downloading.

Building a distinfo file

Now we need to create the SHA256 checksum contained in the distinfo file associated with the port.

Ports has your back! make makesum will generate your distinfo file!

qbit@qbit[0]:/usr/ports/www/py-flask-loginλ make makesum
===>  Checking files for py-flask-login-0.2.11
>> Fetch http://pypi.python.org/packages/source/F/Flask-Login/Flask-Login-0.2.11.tar.gz
Flask-Login-0.2.11.tar.gz 100% |***************************************************************************************************************************************| 11099       00:00    
>> Checksum file does not exist
qbit@qbit[0]:/usr/ports/www/py-flask-loginλ cat distinfo                                                                                                                                      
SHA256 (Flask-Login-0.2.11.tar.gz) = g9XxDlxPIU/u1sxBwhLbY6WKFawy5W34FZG/oKXO4+U=
SIZE (Flask-Login-0.2.11.tar.gz) = 11099

Finishing up

Next steps are:

• create pkg/DESCR
• install your package!
• repeat!

Once all the reqs are in, we are ready to print with OctoPrint!